The invention generally relates to methods and devices for installing in a tubular shaft multiple strain gages, and more particularly to a method and a device for pneumatically forcing strain gages into seated engagement with the internal surfaces of a tubular shaft in an installation of multiple strain gages in a tubular shaft. The essence of the invention involves the novel concept of seating strain gages or other electronic devices in a template-like component, wrapping the template-like component about a pneumatically expansible body, inserting the component into a shaft and expanding the body pneumatically, a suitable adhesive having been applied to the surfaces.
2. Description of the Prior Art
Heretofore, mechanical devices have been constructed for use in installing strain gages in tubular shafts such as the torsion shaft for the canard of F-16 aircraft.
Unfortunately, mechanical devices heretofore employed have not satisfactorily served their intended purposes. For example, installed strain gages, installed utilizing the mechanical prior art devices, frequently undergo displacement or dislodgement, further, the strain gages are often lost. Also, the number of strain gages that can be installed at one time is minimal, and an inordinate amount of time is involved in the attachment of the gages when utilizing the mechanical devices and methods of the prior art. As a consequence, it is generally accepted that installation of strain gages in tubular shafts is a difficult task requiring an inordinate amount of time, and is normally attended by some degree of inaccuracy.
As a consequence of the aforementioned inadequacies of the methods and devices of the prior art, it should be apparent that there currently exists a need for a simplified method and apparatus which can readily be employed in rapidly and accurately mounting strain gages in tubular shafts without the disadvantages which attend the methods and devices previously employed for such purposes.
During the course of a preliminary search conducted for the instant invention, certain patents were discovered which are believed to be pertinent, but fail to teach the instant invention. These patents are listed on the enclosed Form PTO-1449.
While the patents discovered during the course of the search indicate that pneumatically expansible devices heretofore have been employed in joining various materials to the internal surfaces of a tubular body, none of the references discovered in the course of the search contain any suggestion of a method and a device which employs an expansible body for forcing into engagement with the internal surfaces of a tubular shaft, a template-like component having seated therein strain gages to be affixed to the internal surfaces of the shaft.
It is therefore believed that the references discovered in the course of the search clearly fail to disclose the invention hereinafter more fully described and claimed.
It is, therefore, the general purpose of the instant invention to provide a practical and economical method and device which can readily be employed in expeditiously and accurately mounting strain gages at desired locations on the internal surfaces of tubular shafts and the like, such as the torsion shaft for the canard of F-16 aircraft.